This proxy statement and the enclosed proxy card are being
furnished in connection with the solicitation of proxies by the
board of directors of Alnylam Pharmaceuticals, Inc. for use at
the Annual Meeting of Stockholders to be held on Tuesday,
June 3, 2008 at 9:00 a.m., local time, at the offices
of Alnylam Pharmaceuticals, Inc., 300 Third Street, Cambridge,
Massachusetts, and at any adjournment thereof.

All proxies will be voted in accordance with the instructions
contained in those proxies. If no choice is specified, the
proxies will be voted in favor of the matters set forth in the
accompanying Notice of Meeting.

Our Annual Report to Stockholders and our Annual Report on
Form 10-K
for the fiscal year ended December 31, 2007 are being
mailed to stockholders with the mailing of these proxy materials
on or about May 1, 2008.

Important Notice Regarding the Availability of Proxy
Materials for the Annual Meeting of Stockholders to be Held on
June 3, 2008:

This proxy statement and our 2007 Annual Report to
Stockholders are available for viewing, printing and downloading
atwww.alnylam.com/2008AnnualMeeting.

A copy of our Annual Report on
Form 10-K
for the fiscal year ended December 31, 2007, as filed with
the Securities and Exchange Commission, or SEC, will be
furnished without charge to any stockholder upon written request
to Alnylam Pharmaceuticals, Inc., 300 Third Street, Cambridge,
Massachusetts 02142, Attention: Investor Relations and Corporate
Communications. This proxy statement and our Annual Report on
Form 10-K
for the fiscal year ended December 31, 2007 are also
available on the SECs website at www.sec.gov.